Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm

Injection drug use is associated with repeat irrigation and debridement in native joint septic arthritis

Background and objective

Septic arthritis is an orthopaedic emergency that requires prompt irrigation and debridement (I&D). Some patients require a repeat I&D, which poses excessive burden on the patient and provider. The goal of this study was to identify possible risk factors for repeat I&D in the setting of native septic arthritis.

Materials and methods

Consecutive patients with a primary diagnosis of native joint septic arthritis from June 2014-November 2018 at two level-one trauma centers were retrospectively identified via billing codes. Patients were included if they had a clinical presentation consistent with native septic arthritis. Independent-sample T-tests, Fisher's Exact Tests, and multivariable logistic regression were performed to determine what risk factors for repeat I&D were statistically significant.

Results

Two-hundred and twenty-one patients were identified, and 192 were included in the final analysis (36 % female, 64 % male, mean age 53 years). 231 joints were included in the analysis (knee, n = 115; hip, n = 53; shoulder, n = 37; other, n = 16). 29 % of septic joints were associated with injection drug use (IDU-SA). 30 % of IDU-SA cases required a repeat I&D compared to 17 % for non IDU-SA cases (p = 0.03). IDU-SA patients were associated with more total I&Ds compared to patients without IDU-SA (1.70 vs. 1.32; p = 0.048). This association remained significant when controlling for smoking history, diabetes, human immunodeficiency virus, immunocompromised status, and steroid use.

Conclusions

IDU-SA was associated with repeat I&D. Physicians working with IDU-SA patients should alter postoperative surveillance standards and consider adopting a multimodal team approach to improve septic arthritis management.

Admission Neutrophil-to-Lymphocyte Ratio Is Superior to WBC Count at Predicting the Presence and Severity of Pediatric Musculoskeletal Infection

BACKGROUND

Accurately determining the presence and severity of pediatric musculoskeletal infection (MSKI) is crucial for effective triage and treatment. Although the white blood-cell (WBC) count is often used as a marker for MSKI, we hypothesized that the use of the WBC count is limited by age-related variability in children. We proposed that the absolute neutrophil-to-lymphocyte ratio (NLR), which has less age-related variability, is a more reliable indicator for both diagnosing and assessing the severity of MSKI. The present study aims to compare the utility of WBC against that of the NLR, as well as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), for predicting MSKI presence and severity in children.

METHODS

A retrospective cohort study was conducted with use of a database of pediatric orthopaedic consultations for suspected MSKI between January 2013 and July 2022. Diagnoses were categorized as MSKI or no infection, and the severity of any present infection was stratified as local or disseminated. Admission laboratory values were collected. Statistical modeling was performed to assess the capabilities of the WBC, NLR, CRP, and ESR to diagnose MSKI and to assess infection severity, with cutoff thresholds established for clinical use.

RESULTS

This study included 650 patients (median age, 5.2 years; 63% male; 75% White). Of these, 247 patients had no infection, while 403 were diagnosed with an MSKI. Median WBC count, NLR, CRP, and ESR were all significantly higher in pediatric cases of confirmed MSKI. WBC was a poor predictor of infection severity, whereas NLR, CRP, and ESR each positively correlated with infection severity. At the time of admission, an NLR of 4 was highly specific for detecting the presence of infection, and an NLR of 5.8 was highly specific for predicting infection dissemination. CRP was the best predictor of both infection presence and severity, demonstrating the highest specificity and sensitivity, followed by NLR, which outperformed ESR and WBC.

CONCLUSIONS

Because of considerable age-related variability, the predictive value of the WBC count for pediatric MSKI presence and severity is limited. NLR, which is less affected by age-related variability, is superior at predicting MSKI severity. Although CRP remains the benchmark, the NLR offers a valuable alternative to the WBC. Our study provides a comparative framework for these biomarkers, enhancing MSKI assessment across various clinical settings.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The beauty of pediatric musculoskeletal ultrasound

Ultrasound is a powerful technique in pediatric imaging and musculoskeletal (MSK) imaging in many specific clinical scenarios. This article will feature some common and less common spot diagnoses in pediatric musculoskeletal ultrasound.Cases were collected by members of the Educational Committee of the ESSR (European Society of musculoSkeletal Radiology) and the Pediatric Subcommittee of the ESSR with expertise in musculoskeletal ultrasound.Fifteen clinical entities are discussed based on the features that allow diagnosis by ultrasound.Clinical history, location, and ultrasound appearance are the keys to spot diagnoses when performing pediatric musculoskeletal ultrasound. · Ultrasound in pediatric musculoskeletal imaging can achieve a diagnosis in specific clinical settings.. · Clinical history, location, and ultrasound appearance are keys to spot diagnoses.. · Knowledge of spot diagnoses in pediatric musculoskeletal ultrasound facilitates daily clinical practice.. · Drakonaki EE, Adriaensen M, Simoni P et al. The beauty of pediatric musculoskeletal ultrasound. Rofo 2025; 197: 172-185.

Differentiating Between Knee Septic Arthritis and Lyme Arthritis in Children: A Clinical Prediction Algorithm for a Geographically Diverse Population

BACKGROUND

Knee septic arthritis (SA) and Lyme arthritis (LA) often have similar presentations but bacterial SA necessitates urgent surgery. Predictive factors for differentiating SA and other infectious/inflammatory conditions have been published. Our purpose was to test these algorithms using a retrospective multicenter musculoskeletal infection database.

METHODS

Patients ≤18 years old with isolated knee SA or LA were identified. Diagnostic criteria for SA were synovial WBC count >50,000 cells/mm 3 , imaging with fluid aspiration suggestive of SA, or joint aspirate/tissue sample cultured positive for bacteria. Diagnostic criteria for LA was positive Lyme titer. Demographics, weightbearing status, admission vitals, and laboratory tests were collected. Predictive factors from Baldwin criteria for differentiating knee SA and LA, and Kocher criteria for differentiating hip SA and transient synovitis were tested.

RESULTS

One hundred fifty-five patients (119 SA and 36 LA) were analyzed. Patients with SA were younger (2.2 vs. 8.0 y), more nonweightbearing (74% vs. 33%), had a higher pulse (127 vs. 106), and higher WBC (12.4 vs. 10.2) (all P <0.001).Baldwin criteria (pain with joint motion, history of fever, CRP >40 mg/L, age <2 y) were tested. Pain with motion was not collected in our database. Of the remaining factors, the probability of SA was 63% with 0 and 92% with 3 factors (AUC 0.64). Kocher criteria (nonweightbearing, temperature >101.3°F, WBC >12.0, ESR >40) and CRP >20 mg/L were also tested. The probability of SA was 41% with 0 and 96% with all factors (AUC 0.69).Using our cohort data, regression analysis with backward stepwise elimination determined that age <4 years, nonweightbearing, admission WBC >13.0, platelets <325, and ESR >70 were predictive factors for SA. The probability of SA with 0 factors was 16%, 1 factor 52%, 2 factors 86%, 3 factors 97%, and 4 factors 100% (AUC 0.86).

CONCLUSIONS

Our model identified age <4 years, nonweightbearing, admission WBC >13.0, platelets <325, and ESR >70 as independent predictive factors for knee SA. The more factors present, the higher the likelihood of having SA versus LA.

LEVEL OF EVIDENCE

Diagnostic level III.

Clinical indicators for distinguishing septic arthritis from paediatric transient synovitis of the hip: a systematic review and meta-analysis

BACKGROUND

Septic arthritis (SA) of the hip joint is a serious infection that can result in irreversible complications. Distinguishing septic arthritis from transient synovitis, the most common cause of hip pain in children, is crucial for preventing severe outcomes. Existing research has primarily focused on identifying clinical signs and laboratory findings that indicate high-risk patients who may need invasive diagnostic procedures; however, results have been inconsistent. This study aims to evaluate the correlation of various clinical indicators in differentiating septic arthritis from pediatric transient synovitis of the hip.

METHODS

This study followed the PRISMA guidelines rigorously and was registered with PROSPERO. We conducted a systematic search of PubMed, Embase, and Cochrane Library databases for relevant literature up to September 2024. Studies included in the analysis were required to evaluate the predictive value of clinical indicators distinguishing septic arthritis and transient synovitis of the hip in children under 18 years of age. The risk of bias and quality of the included studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and RevMan 5.3. Data synthesis was performed using Stata MP-64 18.0 software to facilitate meta-analysis.

RESULTS

A total of eleven studies were ultimately included for the final analysis, comprising 1810 cases. The results of meta-analysis revealed that history of fever emerged as a significant risk factor for differentiating septic arthritis from pediatric transient synovitis of the hip (OR = 6.04, 95% CI = 2.44-14.97, P < 0.001). Other notable risk factors included non-weight-bearing status (OR = 5.23, 95% CI = 1.38-19.75, P = 0.015), erythrocyte sedimentation rate (OR = 3.98, 95% CI = 1.29-12.30, P = 0.017), and serum white blood cell count (OR = 2.73, 95% CI = 1.23-6.03, P = 0.013). In contrast, C-reactive protein was not a significant risk factor (OR = 7.12, 95% CI = 0.59-85.70, P = 0.122).

CONCLUSION

The clinical indicators involving a history of fever, non-weight-bearing status, erythrocyte sedimentation rate, and serum white blood cell count have been identified as cost-effective routine tests with potential value in differentiating septic arthritis from pediatric transient synovitis of the hip. To enhance the reliability of these findings, further prospective studies are essential.

CLINICAL TRIAL NUMBER

Not applicable.

The Price for Delayed Diagnosis of Pediatric Septic Hip: Increased Cost and Poor Outcomes

BACKGROUND

Most authors agree that early diagnosis and treatment of pediatric septic hip, within 4 days of onset of symptoms, is crucially important for good outcomes. In healthcare, value is a function of outcome over cost. The purpose of this study was to determine the clinical outcome and cost, therefore value, associated with early versus delayed treatment of pediatric septic arthritis of the hip.

METHODS

A retrospective review was performed at a single pediatric hospital. Hospital records over 6 years (2011 to 2016) were examined to identify patients who had undergone treatment for primary septic arthritis of the hip. Patient demographics, clinical data at presentation, treatment information, and follow-up data were recorded. Hospital charges at account level were calculated and compared between groups.

RESULTS

Forty-three subjects were identified for analysis. Twelve presented more than 4 days after the onset of symptoms (delayed diagnosis). There was no difference in patient demographics, Kocher criteria, or initial imaging performed between those with early versus delayed diagnosis. The delayed group had significantly longer length of hospital stay (17 vs. 9 d, P =0.003), follow-up needed (56 vs. 19 wk P =0.001), long-term complications (50% vs. 3%, P =0.000), duration of antibiotics (8 vs. 5.5 wk, P= 0.043), greater number of I&Ds (2 vs. 1, P =0.04), more tissue cultures and blood draws (6 vs. 2, P =0.002; and 3 vs. 2 P =0.009, respectively) and more radiographs taken as outpatients (4 vs. 2, P =0.001, respectively). The average total hospital charge (inpatient and outpatient) was $102,774 in the early diagnosis group and $243,411 in the delayed group ( P =0.012).

CONCLUSIONS

Delayed diagnosis of pediatric septic hip correlated with longer length of hospital stay, duration of follow-up, and more long-term complications. These factors contributed to higher total hospital costs and therefore decreased healthcare value.

Prevalence and Risk Factors for Stiffness Following Open Reduction for Developmental Dysplasia of the Hip

OBJECTIVE

Most prior investigations on adverse outcomes after open reduction (OR) for developmental dysplasia of the hip (DDH) have focused on avascular necrosis, redislocation, and residual dysplasia. To our knowledge, no previous study has investigated risk factors for stiffness, an underappreciated source of postoperative morbidity. The goals of this study were to define the entity more clearly and evaluate the prevalence and risk factors for arthrofibrosis after OR for DDH.

METHODS

A retrospective study was conducted, including all open hip reductions for DDH performed by a single surgeon from 2009 to 2022. Preoperative anteroposterior pelvic radiographs were used to calculate superior displacement, which was defined as the distance from the highest point of the proximal femoral metaphysis to the Hilgenreiner line, normalized by pelvic width. Cases treated with premature postoperative bracing cessation and/or referral to physical therapy with a resolution of stiffness within 6 months were categorized as mild arthrofibrosis. Cases that required >6 months of formal physical therapy for persistent range of motion concerns, manipulation under anesthesia, and/or inpatient rehabilitation admission were categorized as significant arthrofibrosis.

RESULTS

This study included 170 hips with a mean age of 21.6 months (range: 6.1 to 93.6 mo) and a mean follow-up of 46.8 months. 156 ORs (91.8%) were done through an anterior approach. Sixty-four patients (37.6%) had a concomitant isolated pelvic osteotomy, and 34 (20.0%) had both pelvic and femoral osteotomies. During the postoperative course, 109 patients (64.1%) had no arthrofibrosis, 38 (22.4%) had mild stiffness, and 23 (13.5%) had significant arthrofibrosis. On multivariable analysis, older age, superior displacement, and concomitant pelvic osteotomy were associated with any degree of arthrofibrosis ( P < 0.05). Children older than 18 months or with dislocations higher than 16% of pelvic width had a 4.7 and 2.7 times higher risk, respectively, of experiencing some degree of stiffness postoperatively.

CONCLUSIONS

Older age, high dislocations, and concomitant pelvic osteotomy without femoral shortening are risk factors for stiffness after OR for DDH. Surgeons should counsel families about the risk of postoperative stiffness, which occurred to some degree in 36% of our patients.

LEVEL OF EVIDENCE

Level IV.

Transient/Toxic Synovitis

Transient synovitis (TS) is a self-limiting inflammatory condition of the joints, predominantly affecting children and characterized by symptoms such as pain, swelling, warmth, and erythema. It is often triggered by an immune response to a viral infection, leading to acute inflammatory arthritis. Diagnosis involves a combination of patient history, physical examinations, imaging techniques, and laboratory tests, although there are no specific laboratory tests for TS. Treatment primarily consists of symptom management through rest, analgesics, and nonsteroidal anti-inflammatory drugs. The condition underscores the importance of distinguishing TS from more serious joint diseases to prevent unnecessary interventions and to ensure appropriate management.

Literature review and case report of septic arthritis and purpura fulminans leading to a child limb amputation as chickenpox complications

Introduction and significance

Chickenpox, induced by the varicella-zoster virus (VZV), generally presents with an itchy rash and fluid-filled blisters. While complications such as pneumonia and sepsis are well-documented, occurrences of septic arthritis and purpura fulminans are exceedingly rare. Septic arthritis following varicella infection is infrequently reported and often attributed to Staphylococcus aureus. Purpura fulminans encompasses disorders characterized by rapidly progressing purpuric lesions, often fatal and associated with consumptive coagulopathy.

Case presentation

The authors present the case of an 8-year-old boy diagnosed with chickenpox who concurrently developed severe left knee pain, erythema, and swelling indicative of septic arthritis, along with a single pustular lesion on his right foot that progressed to purpura fulminans. Laboratory investigations revealed elevated inflammatory markers. Knee ultrasound findings were consistent with septic arthritis, corroborated by synovial fluid analysis. Immediate initiation of empiric antibiotics was undertaken. Further investigation disclosed unusual coagulation parameters, positive autoantibodies, and reduced protein S levels. Treatment included anticoagulation, immunomodulation, and ultimately, amputation.

Clinical discussion

This rare case underscores the complexity of varicella-related complications, representing the first documented instance of simultaneous septic arthritis and purpura fulminans in a pediatric patient. It highlights the necessity of a multidisciplinary approach for accurate diagnosis and management, emphasizing the importance of recognizing rare complications to improve patient outcomes.

Conclusion

This case exemplifies the complexity of varicella-associated complications, showcasing a rare simultaneous occurrence of septic arthritis and purpura fulminans in a pediatric patient. It underscores the importance of a thorough understanding and collaborative management approaches for timely intervention and enhanced clinical outcomes.

Determining the accuracy of the leukocyte esterase reagent strip test in the rapid diagnosis of adult septic arthritis

BACKGROUNDS

Septic arthritis is a dangerous disease that occurs when microorganisms enter synovial fluid. It needs fast and accurate management; otherwise, it can harm the patient's life. Currently, the tests measure WBC and PMN in SF, so we hypothesized to use a proxy that is easier and faster to measure. Leukocyte esterase is an enzyme secreted by neutrophils that can be found in the synovial fluid of SA patients. In this study, we tried to investigate the sensitivity and specificity of leukocyte esterase in diagnosing septic arthritis.

METHODS

We obtained synovial fluid samples from forty-six patients suspected of having septic arthritis and fifty-eight healthy individuals and measured the WBCs, ESR, CRP, PMN, glucose, and protein of SF in 2021. We also used the leukocyte esterase dipstick test to investigate the level of LE in synovial fluid for one minute.

RESULTS

Based on clinical and paraclinical criteria, sixteen out of the forty-six patients were diagnosed with SA. When (++) was considered positive, the sensitivity and specificity of the LE dipstick test for the diagnosis of SA were 93.7% (95% CI: 81.8-100%) and 60% (95% CI: 42.4-77.5%, P = 0.000), respectively. When both (+) and (++) were considered positive, they were 100% and 43.3% (95% CI: 25.6-61.0% P = 0.000), respectively. All the patients in the control group had negative cultures and LE test readings (specificity = 100%).

CONCLUSION

The LE dipstick test can be a valuable diagnostic tool in the initial diagnosis of SA since it is affordable, fast, and reliable.

Impact of delayed presentation and surgical management on radiologic and clinical outcomes of pediatric septic hip

Background

Septic arthritis of the hip joint (septic hip) is the bacterial infection of the hip. Delayed treatment increases the risk of extensive joint damage, systemic infection, prolonged recovery, higher healthcare costs, and long-term disability. This study explores the repercussions of delayed surgical treatment in pediatric septic hip.

Methods

In this observational study, pediatric patients diagnosed with septic hip between 2012 and 2021 were retrospectively selected from a major referral center in Shiraz, Iran. We collected clinical and radiological data, including Kocher score and determined Choi classification in follow-up radiographs. Multivariate logistic regression analysis was used to assess the impact of delay to surgery on the development of clinical sequelae and radiological deformities in the presence of potential confounders of age and Kocher criteria.

Results

Out of 49 children with delayed presentation, 46 survived and entered the study. Mean delay from symptom presentation to admission was 12.67 ± 10.51 days, and mean delay from admission to surgery was 5.33 ± 6.47 days. Of the 46 patients, 28.26% developed clinical sequelae. The Choi classification revealed that 54.35% of patients developed no residual deformity. A multivariate logistic regression analysis indicated a statistically significant association between delay to surgery and the development of radiological deformities (adjusted odds ratio: 1.36, 95% CI: 1.14-1.64, p = 0.001). Additionally, a separate analysis revealed that each additional day of delay was associated with a 12% increase in the odds of clinical sequelae (adjusted odds ratio: 1.12, 95% CI: 1.03-1.22, p = 0.006). Sensitivity analyses confirmed the relationship of delay from admission to surgery in developing both outcomes.

Conclusion

Delay in medical care and surgical management remains the most important factor affecting the outcomes of septic hip. The study underscores the critical role of timely surgical intervention in reducing complications in pediatric septic hip patients.

Imaging of Disease and Normal Variant Patterns in Pediatric Hips

The pediatric hip undergoes significant changes from infancy through adolescence. Proper maturation is crucial for the development of a stable and functional hip joint. Imaging interpretation of the pediatric hip requires distinguishing normal variants and maturation patterns from pathology. We review femoral ossification centers, variants, and conditions that affect the proximal femur, such as Legg-Calvé-Perthes disease; the acetabulum, such as developmental hip dysplasia; the acetabular labrum, such as femoroacetabular impingement; and synovial pathology in children through adolescence. Understanding the spectrum of hip conditions and using advanced imaging techniques are essential for the accurate diagnosis and effective management of pediatric hip disorders.

Paediatric Septic Arthritis of the Hip and the Efficacy of Kocher's Criteria: A Literature Review

Pediatric septic arthritis (SA), an intra-articular infection in children, is considered a surgical emergency. The most commonly affected joints are the lower limb joints. It is more common in children below five years old and in males. Several scoring systems aid in the prediction of the disease and help differentiate it from similar differential diagnoses (such as transient synovitis (TS)). The first and most famous scoring system is Kocher's Criteria (KC), which utilizes a mixture of clinical signs, symptoms, and laboratory markers to predict the likelihood of the diagnosis. This review aims to assess the current literature to look at primary papers comparing the predicted probability of KC to the original probability described therefore evaluating its efficacy and usefulness in today's pediatric population. PubMed was searched using the terms "septic arthritis AND hip AND (Kocher OR Kocher's criteria)," 27 studies resulted, and each study was screened by reading the abstracts. Six studies were included in this review. Inclusion criteria were any study that looked at SA of the hip in the pediatric population prospectively or retrospectively, using KC to help make a diagnosis and looking at the predicted probability of KC. Exclusion criteria included studies looking at adults, joints other than the hip, and papers not assessing the predicted probability. The efficacy of KC for diagnosing SA is not well-supported by current literature. Studies indicate that KC have low specificity for SA, suggesting it should not replace arthrocentesis as the diagnostic gold standard. Clinicians should use this model cautiously, and more extensive, prospective studies are needed to validate its effectiveness.

Utility of Synovial Fluid Biomarkers for Culture-Positive Septic Arthritis in a Lyme Disease-Endemic Region

OBJECTIVE

To evaluate the performance of synovial fluid biomarkers to identify children with culture-positive septic arthritis.

METHODS

We identified children 6 months to 18 years old presenting to a single emergency department between 2007 and 2022 undergoing evaluation for septic arthritis defined by having a synovial fluid culture obtained. Our primary outcome was septic arthritis defined by a positive synovial fluid culture. We evaluated the ability of synovial fluid biomarkers to identify children with septic arthritis using area under the receiver operating characteristic curve (AUC) analyses. We measured the sensitivity and specificity of commonly used synovial fluid biomarkers.

RESULTS

We included 796 children, of whom 79 (10%) had septic arthritis. Compared with synovial white blood cell count (AUC, 0.72; 95% confidence interval [CI], 0.65-0.78), absolute neutrophil count (AUC, 0.72; 95% CI, 0.66-0.79; P = 0.09), percent neutrophils (AUC, 0.66; 95% CI, 0.60-0.71; P = 0.12), and glucose (AUC, 0.78; 95% CI, 0.67-0.90; P = 0.33) performed similarly, whereas protein (AUC, 0.52; 95% CI, 0.40-0.63, P = 0.04) had lower diagnostic accuracy. Synovial fluid white blood cell count ≥50,000 cells/μL had a sensitivity of 62.0% (95% CI, 50.4%-72.7%) and a specificity of 67.0% (95% CI, 63.4%-70.4%), whereas a positive synovial fluid Gram stain had a sensitivity of 48.1% (95% CI, 36.5%-59.7%) and specificity of 99.1% (95% CI, 98.1%-99.7%) for septic arthritis.

CONCLUSIONS

None of the routinely available synovial fluid biomarkers had sufficient accuracy to be used in isolation in the identification of children with septic arthritis. New approaches including multivariate clinical prediction rules and novel biomarkers are needed.

Analysis of poor prognostic factors for septic arthritis of the hip in children: a case series of 76 patients

The clinical characteristics, treatment and outcomes of children with septic arthritis of the hip in our hospital were analyzed to identify the risk factors for a poor prognosis. The clinical data of 76 children with septic arthritis of the hip who were treated at our hospital from January 2010 to December 2020 were retrospectively analyzed. According to the most recent follow-up data, the patients were classified as good prognosis or poor prognosis. The differences between the two groups were analyzed. From January 2010 to December 2020, a total of 76 children with septic arthritis of the hip were admitted to our hospital, comprising 52 (68.4%) with a good prognosis and 24 (31.6%) with a poor prognosis. The risk of a poor prognosis was significantly higher in the group with time from onset to surgery >22 days than in the group with time from onset to surgery <11 days. The risk of poor prognosis in the group with C-reactive protein (CRP) > 100 mg/L was significantly higher than that in the group with CRP < 20 mg/L. Time from onset to surgery >14 days and CRP > 93 mg/L were the cutoff values for a poor prognosis. Significant elevation of CRP and prolonged time from onset to surgery in children with septic arthritis of the hip are risk factors for a poor prognosis. Early diagnosis and effective treatment are very important because delays in these factors can lead to a poor prognosis. Level of Evidence: Level II, retrospective study.

Optimizing Advanced Imaging of the Pediatric Patient in the Emergency Department: Technical Report

Advanced diagnostic imaging modalities, including ultrasonography, computed tomography, and magnetic resonance imaging, are key components in the evaluation and management of pediatric patients presenting to the emergency department. Advances in imaging technology have led to the availability of faster and more accurate tools to improve patient care. Notwithstanding these advances, it is important for physicians, physician assistants, and nurse practitioners to understand the risks and limitations associated with advanced imaging in children and to limit imaging studies that are considered low value, when possible. This technical report provides a summary of imaging strategies for specific conditions where advanced imaging is commonly considered in the emergency department. As an accompaniment to the policy statement, this document provides resources and strategies to optimize advanced imaging, including clinical decision support mechanisms, teleradiology, shared decision-making, and rationale for deferred imaging for patients who will be transferred for definitive care.

Optimizing Advanced Imaging of the Pediatric Patient in the Emergency Department: Technical Report

Advanced diagnostic imaging modalities, including ultrasonography, computed tomography, and magnetic resonance imaging (MRI), are key components in the evaluation and management of pediatric patients presenting to the emergency department. Advances in imaging technology have led to the availability of faster and more accurate tools to improve patient care. Notwithstanding these advances, it is important for physicians, physician assistants, and nurse practitioners to understand the risks and limitations associated with advanced imaging in children and to limit imaging studies that are considered low value, when possible. This technical report provides a summary of imaging strategies for specific conditions where advanced imaging is commonly considered in the emergency department. As an accompaniment to the policy statement, this document provides resources and strategies to optimize advanced imaging, including clinical decision support mechanisms, teleradiology, shared decision-making, and rationale for deferred imaging for patients who will be transferred for definitive care.

Investigation and Management of Lower Limb Septic Arthritis in Children: An Update Using the Latest British Orthopaedic Association Standard for Trauma (BOAST) Guidelines

Septic arthritis is a serious condition in children, with the hip and knee joints most typically affected. Patients typically present with pain, joint swelling, fever, and an inability to bear weight. Early recognition and treatment are crucial, as untreated septic arthritis can lead to serious complications, including sepsis, irreversible joint damage, growth problems, and early-onset arthritis. Clinical signs, inflammatory markers, and imaging are used for the diagnosis of septic arthritis. The mainstay of management includes antibiotic therapy and surgical washout. Long-term follow-up is essential to monitor for complications.

Transient synovitis of the hip: Development and validation of a new diagnostic algorithm

AIM

To develop and validate an algorithm to rapidly distinguish transient synovitis (TS) of the hip from differential diagnoses without additional tests.

METHODS

This retrospective cohort study included all children admitted for non-traumatic limping in the emergency department at Lille University-Hospital between 2016 and 2020. The gold standard was a definitive diagnosis at follow-up visit. All variables associated with acute limping in children were analysed in univariate and multivariable analyses. An algorithm was then developed using recursive partitioning and validated internally on a subset of patients.

RESULTS

There were 995 patients included (mean age 5.3 years; males 63%); 337 had a TS including 210 confirmed at follow-up visit and 354 another diagnosis. After multivariable analysis, the relevant variables for distinguishing between TS and differential diagnoses were: age 3-10 years, absence of fever, absence of local inflammation, sudden onset of limping on awakening. An algorithm combining these variables was developed (n = 297) and validated internally (n = 175) for children >12 months with limping for ≤10 days, with a specificity of 98.2% and a positive likelihood ratio of 19.6. No serious differential diagnoses were missed.

CONCLUSION

Use of this algorithm enables the diagnosis of TS without additional tests and without missing serious differential diagnoses.

Increased risk of osteomyelitis and septic arthritis in osteogenesis imperfecta

We investigated the prevalence of osteomyelitis and septic arthritis in individuals with osteogenesis imperfecta (OI) as compared to the general population. We performed a retrospective cohort study utilizing the TriNetX Analytics platform, a federated, aggregated electronic health record (EHR) research network containing national, deidentified EHR data. We queried patients with OI, based on encounter diagnoses. Patients in this group with any occurrence of osteomyelitis or septic arthritis were recorded. A control cohort was established to compare the prevalence in patients without OI. Of 8444 individuals with OI, 433 (5.13%) had encounter diagnoses for osteomyelitis and 61 (0.72%) had encounter diagnoses for septic arthritis. In comparison, of 79 176 436 patients without OI, 352 009 (0.44%) had encounter diagnoses for osteomyelitis, while 106 647 (0.13%) had encounter diagnoses for septic arthritis. The relative risk for osteomyelitis in OI patients was 11.53 (95% CI: 10.52-12.64), while the relative risk for septic arthritis was 5.36 (95% CI: 4.18-6.89). The relative risk for osteomyelitis in pediatric OI patients was 30.55 (95% CI: 24.35-38.28). To our knowledge, this is the first study investigating musculoskeletal infections in patients with OI, as well as the first to report the overall prevalence in the general population. Clinicians may benefit from a high index of suspicion for musculoskeletal infections in OI patients with corresponding symptoms. Further study is warranted to investigate if modifications to conventional diagnostic pathways and criteria are valuable in this population. Level of evidence: Retrospective Cohort Study - Level II.

Atraumatic Limping Child, a Challenge for Pediatricians: An Observational Age-Related Study in a Pediatric Emergency Department

BACKGROUND

Atraumatic limping is a frequent cause of consultation in Pediatric Emergency Departments (PED) and often represents a challenge for pediatricians for its variability in etiology ranging from benign causes to potential crippling conditions. The aims of this research are to illustrate the clinical features of acute limping children (LC) and to identify the possible red flags that could help to make a diagnosis of severe pathologies.

METHODS

We carried out a retrospective study about non-traumatic limping children referred to the PED of Bambino Gesù Children's Hospital over a 2-year period. We divided the cohort into three groups based on the patient's age: toddlers, children and adolescents. We considered crippling conditions: oncologic etiologies, bone or neurological infections, epiphysiolysis, Perthes disease, Guillain Barrè syndrome and non-accidental injuries.

RESULTS

We analyzed 485 patients. At clinical evaluation, 19.5% of the patients presented at least one sign and/or symptom of red flags. Crippling conditions (6.2% of the total population) showed red flags in 36.7%. Transient synovitis of the hip was the most frequent diagnosis. We found crippling conditions in 30 patients, mostly represented by toddlers.

CONCLUSIONS

Our data suggest that toddlers and patients presenting red flags should be evaluated with particular suspicion because they have an increased risk of underlying severe conditions.

Clinical Practice Guideline by the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA): 2023 Guideline on Diagnosis and Management of Acute Bacterial Arthritis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute bacterial arthritis (ABA) in children was developed by a multidisciplinary panel representing the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with ABA, including specialists in pediatric infectious diseases and orthopedics. The panel's recommendations for the diagnosis and treatment of ABA are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of ABA in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) (see Figure 1). A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

A Case of Hematogenous Osteomyelitis in a 5-Week-Old Male

Pediatric osteomyelitis is a rare diagnosis associated with devastating consequences when treatment is delayed. We report a case of hematogenous osteomyelitis in a 5-week-old male presenting to the emergency department (ED) with a flaccid right upper extremity. In the ED, the patient was evaluated with comprehensive infectious and trauma workups. Initial CT imaging of the head and X-ray imaging of the extremity were unremarkable. C-reactive protein was elevated at 0.8; all other laboratory markers were within normal range. Over the course of the ED evaluation, the extremity weakness spontaneously resolved; however, the infant developed a fever of 100.5 F. Empiric broad spectrum antibiotics were initiated, and the infant was admitted to the pediatric service. At 48 hours following presentation, cultures resulted positive for Staphylococcus aureus and MRI imaging revealed osteomyelitis of the proximal right humeral metadiaphysis. Given the subtle presentation of early hematogenous osteomyelitis, emergency providers should maintain a high index of suspicion for infection as the underlying cause in infants presenting with a flaccid extremity.

A Novel Risk Score to Guide the Evaluation of Acute Hematogenous Osteomyelitis in Children

OBJECTIVES

To identify independent predictors of and derive a risk score for acute hematogenous osteomyelitis (AHO) in children.

METHODS

We conducted a retrospective matched case-control study of children >90 days to <18 years of age undergoing evaluation for a suspected musculoskeletal (MSK) infection from 2017 to 2019 at 23 pediatric emergency departments (EDs) affiliated with the Pediatric Emergency Medicine Collaborative Research Committee. Cases were identified by diagnosis codes and confirmed by chart review to meet accepted diagnostic criteria for AHO. Controls included patients who underwent laboratory and imaging tests to evaluate for a suspected MSK infection and received an alternate final diagnosis.

RESULTS

We identified 1135 cases of AHO matched to 2270 controls. Multivariable logistic regression identified 10 clinical and laboratory factors independently associated with AHO. We derived a 4-point risk score for AHO using (1) duration of illness >3 days, (2) history of fever or highest ED temperature ≥38°C, (3) C-reactive protein >2.0 mg/dL, and (4) erythrocyte sedimentation rate >25 mm per hour (area under the curve: 0.892, 95% confidence interval [CI]: 0.881 to 0.901). Choosing to pursue definitive diagnostics for AHO when 3 or more factors are present maximizes diagnostic accuracy at 84% (95% CI: 82% to 85%), whereas children with 0 factors present are highly unlikely to have AHO (sensitivity: 0.99, 95% CI: 0.98 to 1.00).

CONCLUSIONS

We identified 10 predictors for AHO in children undergoing evaluation for a suspected MSK infection in the pediatric ED and derived a novel 4-point risk score to guide clinical decision-making.

The Limping Child: A Guide for the Trainees

Limping is a common presenting complaint in children. Despite this, it remains to be a diagnostic challenge for treating physicians due to an expanded list of etiologies. It arises from a spectrum of disorders, ranging from physiological variations of gait at different stages of development to systemic causes, such as inflammatory diseases or musculoskeletal infections. On rare occasions, non-musculoskeletal causes could result in limping. The diagnostic challenge increases in younger age children where a detailed physical examination that helps identify the exact source of pathology may not be possible. In older patients who have a well-developed gait cycle, the physical assessment might be easier. Clinical assessment in a child presenting with a limp includes gait analysis, which is essential to guide the appropriate request of diagnostic laboratory tests and imaging studies. In this paper, we provide a practical guide for a trainee in General Pediatric and Pediatric Rheumatology on an approach to a limping child, aiming to identify the common causes of limping and to describe normal and abnormal gait cycles. We also discuss other diagnostic considerations in the assessment of these children.

Septic arthritis in the pediatric hip joint: a systematic review of diagnosis, management, and outcomes

Septic arthritis of the pediatric hip joint (SAH) is a rare but serious orthopedic emergency requiring immediate diagnosis and management. Delayed recognition can lead to severe complications, emphasizing the need for timely intervention. This systematic review aims to provide a comprehensive analysis of SAH in the pediatric population, focusing on its diagnosis, management, and outcomes. The review included 11 studies involving 391 patients with SAH, aged between three months and 12 years. Staphylococcus aureus was identified as the most common causative pathogen, with increasing cases of methicillin-resistant strains. Diagnosis is challenging due to nonspecific clinical presentations, necessitating validated criteria and a multidisciplinary approach. Ultrasound emerged as a valuable tool for early detection, and MRI was used in challenging cases. Treatment options include hip aspiration, arthrotomy, and arthroscopy, often combined with appropriate antibiotic therapy. Success rates were comparable among different surgical procedures. Early intervention is vital for optimal outcomes. However, the review highlights the need for standardized protocols and further prospective studies to address limitations and improve understanding and management of SAH in the pediatric hip joint.

Role of ultrasound and inflammatory factors in the management of pediatric hip joint effusion

BACKGROUND

Septic arthritis is an important differential diagnosis of hip joint pain. Joint aspiration analysis is a necessary diagnostic measure for septic arthritis. In order to reduce the need for joint aspiration, we compared the combination of ultrasound findings and laboratory findings to separate septic arthritis from reactive arthritis.

METHODS

Children aged < 14 years who were referred to Akbar pediatric hospital in 2020-2022 with hip pain or limping were included in this longitudinal study. Participants underwent ultrasound examinations of the hip and blood samples were obtained from them. After confirming an effusion, dependent on patient status and clinical diagnosis, one of the following approaches was recommended; the close follow-up, or the ultrasound-guided aspiration of the hip joint effusion, and or arthrotomy. The various ultrasound and laboratory were documented. Data were analyzed and P < 0.001 being considered statistically significant.

RESULTS

Overall, 115 patients with a mean age of 3.43 ± 5.76 years, 46 of whom were girls, were studied. The final diagnosis in 23 cases (20.0%) was septic arthritis and 92 (80.0%) had reactive arthritis. C-reactive protein (CRP) and The erythrocyte sedimentation rate (ESR) unlike aspirate volume, effusion volume measured on ultrasound, capsule thickness, total thickness, and recorded capsule-to-effusion ratio were significantly higher in patients with septic arthritis (P < 0.001). There was a significant agreement between the volume of measured fluid in the anterior recess and the volume of aspirated fluid (2.5 times, P < 0.001). Septic arthritis was not observed in any of the patients with effusion volume in anterior recess less than 0.5 cc and ESR less than 40 mm/hr or CRP less than 15 mg/L.

CONCLUSION

Since septic arthritis was not observed in any of the patients with effusion volume < 0.5 cc and normal inflammatory factors (ESR or CRP), conservative management and close follow-up can be recommended in these patients instead of joint fluid aspiration.

Sore knee - why and when to call a cardiologist

A young girl received a diagnosis of septic arthritis of the knee unresponsive to standard medical and surgical treatment. We report the patient's clinical journey with clinical commentary throughout, underlying the importance of differential diagnosis that may open several scenarios and a different final diagnosis accordingly. Finally, we will discuss the treatment and management of the patient's final diagnosis.

What's New in Pediatric Septic Arthritis? A Review of Pertinent Clinical Questions

BACKGROUND

The evaluation and treatment of children with septic arthritis (SA) is challenging and requires an organized approach to address the spectrum of pathogens which appear to aggregate in age-specific groups. Although evidence-based guidelines have recently been published for the evaluation and treatment of children with acute hematogenous osteomyelitis, there is a relative dearth of literature devoted exclusively to SA.

METHODS

Recently published guidance for the evaluation and treatment of children with SA was reviewed and evaluated with respect to pertinent clinical questions to summarize what is new in this area of practice for pediatric orthopaedic surgeons.

RESULTS

Evidence suggests that there is a profound difference between children with primary SA and those who have contiguous osteomyelitis. This disruption of the commonly accepted paradigm of a continuum of osteoarticular infections has important implications in the evaluation and treatment of children with primary SA. Clinical prediction algorithms have been established to help determine the applicability of magnetic resonance imaging during the evaluation of children suspected to have SA. Antibiotic duration for SA has been recently studied with some evidence in favor of short-course parenteral followed by short-course oral therapy may be successful if the pathogen is not methicillin-resistant Staphylococcus aureus .

CONCLUSION

Recent studies of children with SA have provided better guidance for evaluation and treatment to improve diagnostic accuracy, processes of evaluation, and clinical outcomes.

LEVEL OF EVIDENCE

Level 4.

Late-Presenting Septic Arthritis of the Hip in Children: Variations in Presentation and a Review of 25 Hips After Surgical Debridement

INTRODUCTION

The septic arthritis of the hip (SAH) is one of the most common musculoskeletal infections occurring in pediatric populations requiring urgent intervention. This study discusses the myriad of clinical and radiological presentations of late-presenting SAH in children and the outcomes of surgical management.

METHODS

After ethical approval, we did retrospective reviews of children treated for late-presenting SAH (after five days of symptoms). We excluded late cases with established sequelae. We recorded age, duration of symptoms, clinical evaluation, and radiographs. We evaluated the final results clinically and radiologically.

RESULTS

Twenty-four patients with 25 hips were eligible for evaluation. At presentation, all had decreased or painful hip movements, but none had a fever. Radiographs revealed the following changes: hip dislocation (four), capital femoral slip (seven), proximal femur/neck osteomyelitis (six), pathological fractured neck femur (two), iliac osteomyelitis (two), and early arthritic changes (two). Hip arthrotomy was done in all cases. Frank pus was found in 21 (84%) cases. Cases with capital slip and fractured neck femur required fixation with two smooth K-wires. Methicillin-resistant Staphylococcus aureus (MRSA) was isolated in three patients and tuberculosis in two cases. Clinical outcomes showed 14 patients with poor outcomes, eight with fair, and two with good. Avascular necrosis (AVN) of the femoral head was noted in 14 hips and complete femoral head resorption in nine.

CONCLUSIONS

The late-presenting SAH in children has a myriad of presentations including dislocation and capital slip with unsatisfactory outcome. However, ongoing local infective processes may necessitate debridement. With limited salvage options available at the sequelae stage, awareness and training for early diagnosis and treatment may be the best way to improve the scenario. We recommend future multicenter randomized studies of predictive factors and indications of arthrotomy in late presenters.

[Septic arthritis and transient synovitis of the hip]

CLINICAL/METHODICAL ISSUE

Differentiating between septic arthritis and transient synovitis can be challenging but is very important as a late diagnosis of septic arthritis can lead to sepsis and joint damage. For correct diagnosis and prediction of complications, the right combination of physical examination, laboratory and radiological studies is needed.

STANDARD RADIOLOGICAL METHODS

Hip ultrasound is easy to learn and has a high sensitivity for joint effusion. Faster diagnosis and therapy are possible due to increasing use of ultrasound. Magnetic resonance imaging (MRI) is primarily used to rule out co-infections (osteomyelitis, pyomyositis) and differential diagnoses. X‑ray is typically nonremarkable in septic arthritis.

PRACTICAL RECOMMENDATIONS

Routine use of ultrasound in nontraumatic pediatric hip pain. Generous use of MRI in case of elevated inflammatory markers or inconclusive clinical findings. Using only few sequences may be appropriate to avoid sedation, primarily fluid sensitive sequences (fat-saturated T2, TIRM, STIR), in case of positive findings, accompanied by T1-weighted images.

High-resolution ultrasound in the evaluation of musculoskeletal infections

Soft tissue and osseous musculoskeletal infections are common but can be difficult to diagnose clinically. Signs, symptoms, and physical examination findings may be nonspecific, and laboratory values can be inconclusive. The extent of disease may also be underestimated on physical examination. Soft tissue infections most commonly occur secondary to direct inoculation from broken skin and less frequently due to the seeding of the soft tissues from hematogenous spread, while osseous infections are more commonly due to hematogenous seeding. Infections may also be iatrogenic, following surgery or other procedural interventions. High-resolution ultrasound is an extremely useful imaging modality in the evaluation of musculoskeletal soft tissue and joint infections, and can occasionally be used to evaluate osseous infections as well. Ultrasound can aid in the early diagnosis of musculoskeletal infections, allowing for prompt treatment, decreased risk of complications, and treatment optimization. Ultrasound is sensitive and specific in evaluating soft tissue edema and hyperemia; soft tissue abscesses; joint, bursal and tendon sheath effusions/synovitis; and subperiosteal abscesses. This article describes the typical high-resolution grayscale as well as color and power Doppler ultrasound imaging findings of soft tissue infections including cellulitis, fasciitis, necrotizing deep soft tissue infection, pyomyositis, soft tissue abscess, infectious bursitis, and infectious tenosynovitis. Ultrasound findings of septic arthritis as well as osteomyelitis, such as subperiosteal spread of infection (subperiosteal abscess). are also reviewed. In addition, the use of ultrasound to guide fluid and tissue sampling is discussed.

Biological Predictors of Osteoarticular Infection Due to K. kingae-A Retrospective Cohort Study of 247 Cases

Pediatric osteoarticular infections (OAIs) are serious conditions that can lead to severe septic complications, prolonged morbidity with long-term impaired function, and perturbed subsequent bone development. Kingella kingae (K. kingae) is currently accepted as the predominant pathogen in pediatric OAIs, especially among 6-48 month olds. The present study aimed to identify clinical and biological markers that would refine the detection of patients with an OAI due to K. kingae. We retrospectively studied every consecutive case of pediatric OAI admitted to our institution over 17 years. Medical records were examined for patient characteristics such as temperature at admission, affected segment, and biological parameters such as white blood cell (WBC) count, left shift, platelet count (PLT), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). The 247 patients included 52.2% males and 47.8% females and mean age was 18.5 ± 10 months old. Four patients were older than 48 months; none were younger than 6 months old. Mean temperature at admission was 37.4 ± 0.9 °C. Regarding biological parameters, mean WBC count was 12,700 ± 4180/mm3, left shift was only present in one patient, mean PLT was 419,000 ± 123,000/mm3, mean CRP was 26.6 ± 27.8 mg/L, and mean ESR was 35.0 ± 18.9 mm/h. Compared to the modified predictors of OAI defined by Kocher and Caird, 17.2% of our cases were above their cut-off values for temperature, 52.3% were above the WBC cut-off, 33.5% were above the ESR cut-off, and 46.4% were above the CRP cut-off. OAIs due to K. kingae frequently remain undetected using the classic biological parameters for investigating bacterial infections. As an addition to the predictors normally used (°C, WBC, CRP, and ESR), this study found that elevated platelet count was frequently present during OAIs caused by K. kingae. Although this biological characteristic was inconstant, its presence was highly significant and very suggestive of an invasive infection due to K. kingae.

Pediatric Osteoarticular Kingella kingae Infections of the Hand and Wrist: A Retrospective Study

Our understanding of pediatric osteoarticular infections (OAIs) has improved significantly in recent decades. Kingella kingae is now recognized as the most common pathogen responsible for OAIs in pediatric populations younger than 4 years old. Research has provided a better understanding of the specific types, clinical characteristics, biological repercussions, and functional outcomes of these infections. Hands and wrists are rarely infected, with few reports available in the literature. The present study aimed to examine this specific condition in a large patient cohort, explore the implications for each anatomical area using magnetic resonance imaging (MRI), and critically evaluate the evolution of therapeutic management.

Septic Arthritis of the Elbow in a Premature Neonate: An Uncommon Disease in an Uncommon Location

Septic arthritis (SA) is an infrequent diagnosis in the neonate. This case illustrates the presentation of SA within the elbow, an atypical location for neonatal SA. SA should be considered in any neonate with joint swelling, as symptoms are often subtle. Constitutional symptoms of infection, including fever, may not be present in the neonate. Staphylococcus aureus is the most common etiologic organism, and neonatal SA is often caused by hematogenous spread partially due to unique neonatal intraosseous anatomy. Joint aspiration can provide a definitive diagnosis and aid in targeted antimicrobial therapy. Other laboratory tests, including C-reactive protein and erythrocyte sedimentation rate, can aid in diagnosis. Ultrasound and magnetic resonance imaging can demonstrate joint effusion along with osteomyelitis, which is often seen concurrently with neonatal SA. There are no definitive guidelines for the treatment of neonatal SA. Conservative therapy with antimicrobials along with surgical intervention are the mainstays of treatment. Prompt diagnosis and treatment are crucial to decrease permanent joint damage. [Pediatr Ann. 2023;52(8):e292-e296.].

Clinical and Radiographic Outcomes and Treatment Algorithm for Septic Arthritis in Children

BACKGROUND

Septic arthritis (SA) in children is an acute inflammatory disease of the joints. If not treated promptly, it could become a surgical emergency. The incidence of the disease in children in Europe is approximately 2-7 per 100,000 children. The aim of this systematic review was to investigate which of these treatments-arthrocentesis, arthrotomy, and arthroscopy-provides better results in children and when to use them.

METHODS

Three independent authors conducted a systematic review of PubMed, ScienceDirect, and MEDLINE databases to assess studies with any level of evidence that reported the surgical outcome of SA. Two senior investigators evaluated and approved each stage's findings.

RESULTS

A total of 488 articles were found. After screening, we chose 24 articles that were suitable for full-text reading based on the inclusion and exclusion criteria. The results of our analysis showed that there are no numerically significant differences reported in the literature on clinical and radiographic outcomes by surgical technique.

CONCLUSIONS

We developed an algorithm that could be used if septic arthritis is suspected. Based on our results, the surgical technique to be used will depend on the operator who will perform it.

Evaluation of paediatric hip pain

Hip pain in a child can pose a diagnostic conundrum. In most cases, the cause of a painful hip is often attributed to trauma, but a number of these cases will be atraumatic. The main entities to consider are inflammatory, infective and neoplastic causes. Pathologies such as avascular necrosis and slipped upper femoral epiphysis can also present in a similar manner. A detailed history and clinical examination are crucial in narrowing down the differential diagnosis. In addition, understanding the most appropriate imaging modalities and the characteristic radiological findings is key in ensuring timely treatment and management. This article reviews the various disease processes in children who present with hip pain and outlines the most appropriate assessment and imaging modalities that will aid diagnosis.

Posterior Wall Acetabular Fracture After Low-Energy Trauma Masquerading as Infection: A Case Report

CASE

A 12-year-old adolescent boy presented after a low-energy fall with groin pain, inability to bear weight, painful passive range of motion, fever, elevated inflammatory markers, and upper respiratory symptoms. Initial radiographs did not demonstrate any abnormality, and magnetic resonance imaging suggested infection. Posterior wall acetabular fracture was not diagnosed until a computed tomography-guided biopsy was performed.

CONCLUSION

Pediatric acetabular fractures are exceedingly rare. They can be difficult to diagnose after low-energy trauma as symptoms mimic infectious hip pathologies. Children presenting with infectious hip symptomology and a history of trauma may benefit from more extensive trauma imaging before costly and invasive infectious diagnostic procedures.

Acute musculoskeletal infection in children: assessment and management

Musculoskeletal infection in children is challenging to treat, and includes septic arthritis, deep tissue infection, osteomyelitis, discitis and pyomyositis. Delays to diagnosis and management, and under-treatment can be life-threatening and result in chronic disability. The British Orthopaedic Association Standards for Trauma include critical steps in the timely diagnosis and management of acute musculoskeletal infection in children, the principles of acute clinical care and the service delivery requirements to appropriately manage this cohort of patients. Orthopaedic and paediatric services are likely to encounter cases of acute musculoskeletal infection in children and thus an awareness and thorough understanding of the British Orthopaedic Association Standards for Trauma guidelines is essential. This article reviews these guidelines and associated published evidence for the management of children with acute musculoskeletal infection.

Pediatric musculoskeletal infections

PURPOSE OF REVIEW

The aim of this article is to review the recent guidelines and literature regarding the diagnosis and the treatment of common pediatric musculoskeletal infections: septic arthritis, osteomyelitis, pyomyositis, and Lyme disease.

RECENT FINDINGS

In the last decade, a better understanding of the causative organisms of common bacterial infections, including Kingella , leads to prompt targeted antimicrobial coverage in all musculoskeletal infections. Prompt diagnosis and treatment continues to be the mainstay in the treatment of children with osteoarticular infections. Efforts to improve early detection have lead to improving rapid lab diagnostic testing; however, more advanced diagnostics such as arthrocentesis for septic arthritis and MRI for osteomyelitis and pyomyositis, remain the gold standard. Shorter and narrowed antibiotic courses, with appropriate transition to outpatient oral treatment provide effective infection clearance and reduction in complications of disease.

SUMMARY

Advances in diagnostics, including pathogen identification as well as imaging continues to improve our ability to diagnose and treat these infections, although still lack ability to provide definitive diagnosis without more invasive nor advanced techniques.

Relevant factors in the diagnosis of concomitant osteomyelitis in pediatric hip septic arthritis. A series of 41 cases treated by hip arthroscopy

INTRODUCTION

Septic arthritis of the hip can appear isolated or concomitant with pelvic osteomyelitis. Delay in the diagnosis of a concomitant osteomyelitis increases the number of required surgeries and of possible complications.

PURPOSE

This study aims to establish relevant factors in the diagnosis of concomitant osteomyelitis in cases with septic arthritis of the hip among paediatric patients.

METHODS

The data were collected between 2005 and 2020. 41 pediatric patients with suspicion of septic arthritis of the hip joint, treated arthroscopically, were included. The following diagnostic test parameters were collected: ultrasound, MRI, X-Rays, blood samples, temperature, and incapacity to bear weight. The data were analysed with the sensitive analysis method using descriptive statistic.

RESULTS

41 patients were analyzed, with an average age of 6.04 y (7 months to 14 years), of which ten patients (24.39%) presented concomitant osteomyelitis. 6 out of ten patients needed secondary surgery. Regarding age, concomitant osteomyelitis was most common in the age group 4-14 years old. Average number of days of clinical symptoms before admission was 6.2 days. 36/41 cases showed CRP values higher than 2 mg/dl. 9/10 cases with concomitant osteomyelitis showed a CRP > 2 mg/dl, with an average value of 8.9 mg/dl. 22/41 patients underwent an MRI, of which nine cases presented a concomitant osteomyelitis. The probability of a child to have septic arthritis of the hip with adjacent osteomyelitis was analysed through a score based on four factors: impossibility to bear weight and/or hip pain in children in the non-walking age category, CRP > 2 mg/dl, age older than > 4 y, symptoms longer than 4 days.

CONCLUSIONS

Children at the age of walking, with incapacity to bear weight, presenting symptoms longer than 4 days and a CRP > 2 mg/dl, should receive an MRI before surgery to exclude adjacent osteomyelitis.

LEVEL OF EVIDENCE

IV.

Surgical treatment of septic arthritis of the hip in children: arthrotomy compared with repeated aspiration-lavage

PURPOSE

To review two cohorts of children treated by two different protocols (repeated needle aspiration-lavage vs. arthrotomy) for surgical treatment of septic arthritis of the hip (SAH).

METHODS

In order to compare between the two methods, the following parameters were checked: (a) Scar cosmesis was assessed by the Patient and Observer Scar Assessment Scale (POSAS). We considered satisfactory results (no scar discomfort) when POSAS was within 10% of the ideal score; (b) 24-h post-operative pain was evaluated by visual analog scale (VAS); (c) Complication rates of incomplete drainage (re-arthrotomy/therapy modification from aspiration-lavage to arthrotomy). The results were evaluated by the Student t-test or by the chi-square test.

RESULTS

Seventy-nine children (aged 2-14 years) admitted during 2009-2018 and available for at least two years of follow-up were enrolled. The POSAS score (range 12-120 points) at the latest follow-up was higher in the arthrotomy group compared with the aspiration-lavage group (18.10 ± 6.22 versus 12.27 ± 1.40, p < 0.001); 77.4% of patients treated by arthrotomy had no scar discomfort. The 24-h post-intervention VAS (range 1-10) was 5.06 ± 1.29 after arthrotomy and 4.03 ± 1.13 after aspiration-lavage, p < 0.04. Complications were three times more frequent in the aspiration-lavage group (8.8% in the arthrotomy group and 26.7% in the aspiration-lavage group, p = 0.045).

CONCLUSIONS

We conclude that the lower complication rate observed in the arthrotomy group outweighs by far scar cosmesis and post-operative pain advantages in the aspiration-lavage group. Arthrotomy as a drainage method is safer than aspiration-lavage.

Atypical Staphylococcal Septic Arthritis in a Native Hip: A Case Report and Review

Septic arthritis is a synovial fluid and joint tissue infection with significant morbidity and mortality risk if not diagnosed and treated promptly. The most common pathogen to cause septic arthritis is Staphylococcus aureus, a Gram-positive bacterium. Although diagnostic criteria are in place to guide the diagnosis of staphylococcal septic arthritis, there is a lack of adequate sensitivity and specificity. Some patients present with atypical findings which make it difficult to diagnose and treat in time. In this paper, we present the case of a patient with an atypical presentation of recalcitrant staphylococcal septic arthritis in a native hip complicated by uncontrolled diabetes mellitus and tobacco usage. We review current literature on diagnosing S. aureus septic arthritis, novel diagnostic technique performance to guide future research and assist clinical suspicion, and current S. aureus vaccine development for at-risk patients.

Clinical and Biologic Characteristics of Kingella kingae -Induced Septic Arthritis of the Knee in Young Children

BACKGROUND AND OBJECTIVES

Septic arthritis of the knee is presumed to be the most frequent form of Kingella kingae -induced osteoarticular infection. This study aimed to report on the clinical course, biological parameters, and results of microbiological investigations among children with K. kingae -induced septic arthritis of the knee. It also assessed the modified Kocher-Caird criteria's ability to predict K. kingae -induced septic arthritis of the knee.

METHODS

The medical charts of 51 children below 4 years old with confirmed or highly probable K. kingae -induced arthritis of the knee were reviewed. Data were gathered on the five variables in the commonly-used Kocher-Caird prediction algorithm (body temperature, refusal to bear weight, leukocytosis, erythrocyte sedimentation rate, and C-reactive protein level).

RESULTS

Patients with K. kingae -induced arthritis of the knee usually presented with a mildly abnormal clinical picture and normal or near-normal serum levels of acute-phase reactants. Data on all five variables were available for all the children: 7 children had zero predictors; 8, 20, 12, and 4 children had 1, 2, 3, and 4 predictors, respectively; no children had 5 predictors. This gave an average of 1.96 predictive factors and a subsequent probability of ≤ 62.4% of infectious arthritis in this pediatric cohort.

CONCLUSIONS

Because the clinical features of K. kingae -induced arthritis of the knee overlap with many other conditions affecting this joint, the Kocher-Caird prediction algorithm is not sensitive enough to effectively detect K. kingae -induced septic arthritis of the knee. Excluding K. kingae -induced arthritis of the knee requires performing nucleic acid amplification assays on oropharyngeal swabs and joint fluid from those young children presenting with effusion of the knee, even in the absence of fever, leukocytosis, or a high Kocher-Caird score.

Diagnosing acute bone and joint infection in children

Acute bone and joint infections in children are serious, and misdiagnosis can threaten limb and life. Most young children who present acutely with pain, limping, and/or loss of function have transient synovitis, which will resolve spontaneously within a few days. A minority will have a bone or joint infection. Clinicians are faced with a diagnostic challenge: children with transient synovitis can safely be sent home, but children with bone and joint infection require urgent treatment to avoid complications. Clinicians often respond to this challenge by using a series of rudimentary decision support tools, based on clinical, haematological, and biochemical parameters, to differentiate childhood osteoarticular infection from other diagnoses. However, these tools were developed without methodological expertise in diagnostic accuracy and do not consider the importance of imaging (ultrasound scan and MRI). There is wide variation in clinical practice with regard to the indications, choice, sequence, and timing of imaging. This variation is most likely due to the lack of evidence concerning the role of imaging in acute bone and joint infection in children. We describe the first steps of a large UK multicentre study, funded by the National Institute for Health Research, which seeks to integrate definitively the role of imaging into a decision support tool, developed with the assistance of individuals with expertise in the development of clinical prediction tools.

Paediatric acute non-traumatic limp presenting to the emergency department: a retrospective observational study

BACKGROUND

Acute non-traumatic limp in children has many causes, ranging from common benign and self-limiting disease to serious time-sensitive emergencies such as septic arthritis. We aimed to (1) describe the epidemiology and workup of paediatric acute non-traumatic limp presentation in three Australian EDs and (2) compare investigations and treatment between a tertiary paediatric centre and two non-tertiary centres.

METHODS

A retrospective chart review of children aged 0-16 years, with an initial presentation of non-traumatic limp to three EDs in Melbourne, Australia. Data on presentation, management and outcomes was systematically collected on all eligible patients.

RESULTS

Of 63 941 presentations over a 12-month period, 475 (0.7%) met inclusion criteria. The median (IQR) age of presentation was 5 (3-8) years, with a male predominance (61%). Blood tests and imaging were performed in 39% and 51%, respectively. 34% of presentations had no investigations. The most frequent ED diagnoses were transient synovitis (37%) and viral myositis (16%). 84% were discharged home after ED evaluation. Compared with the two non-tertiary hospitals, children who presented to the tertiary centre were less likely to have any investigation performed (OR=0.41, 95% CI: 0.27 to 0.62, p<0.001) and more likely to be discharged home after evaluation (OR=4.67, 95% CI: 2.79 to 7.81, p<0.001).

CONCLUSION

Although mostly due to benign disorders, an important number of limping children who presented to the ED had serious disease, with approximately one-third of these not diagnosed at the initial ED visit. There is large variation in workup including blood test, imaging and decisions regarding ED disposition.

A New Perspective on the Diagnosis of Septic Arthritis: High-Resolution Thermal Imaging

AIMS

An increase in temperature in an area suspected of septic arthritis is a clinically important finding. The aim of this study is to evaluate temperature changes in septic arthritis with a high-resolution thermal camera.

METHODS

A total of 49 patients, who were evaluated with a prediagnosis of arthritis (septic or non-septic), were included in this study. A temperature increase in the knee with suspected septic arthritis was evaluated by using thermal imaging and compared with the opposite-side joint. Then, in order to confirm the diagnosis, a culture was taken using routine intra-articular aspiration.

RESULTS

The thermal measurements were compared in 15 patients with septic arthritis and 34 patients with non-septic arthritis. The mean temperature was 37.93 °C in the septic group, while it was 36.79 °C in the non-septic group (p < 0.000 *). The mean temperature difference in both joints was 3.40 °C in the septic group, while it was 0.94 °C in the non-septic group (p < 0.000 *). While the mean temperature was 37.10 °C in the group with septic arthritis, it was measured to be 35.89 °C in the group non-septic arthritis (p < 0.020). A very strong positive correlation was found between the difference in the mean temperatures of both groups and the values of the hottest and coldest points (r = 0.960, r = 0.902).

CONCLUSIONS

In the diagnosis of septic arthritis, thermal imagers can be used as a non-invasive diagnostic tool. A quantitative value can be obtained to indicate to a local temperature increase. In future studies, specially designed thermal devices can be developed for septic arthritis.

Institutional performance and validation of severity of illness score for children with acute hematogenous osteomyelitis

A scoring system has recently been published that uses parameters within the first 4-5 days of hospitalization to determine the severity of illness (SOI) in children with acute hematogenous osteomyelitis (AHO). To our knowledge, no additional studies to date have examined the validity of the SOI score outside of the institution of origin. This study evaluates the performance of the SOI score in a retrospective cohort of cases at our institution. Patients admitted to our institution over the past 5 years with AHO who met inclusion and exclusion criteria were analyzed. Parameters including C reactive protein over the first 96 h of hospitalization, febrile days on antibiotics, ICU admission, and presence of disseminated disease were used to calculate the SOI score for each patient. Pearson and Spearman correlations were used when appropriate. SOI score comparison between groups was achieved with the Kruskal-Wallis and Wilcoxon two-sample tests. Seventy-four patients were analyzed. Significantly higher SOI scores were noted for patients with bacteremia, ICU admission, fever for two or more days on presentation, multiple surgeries, and any complication. Markers of disease severity that significantly correlated with SOI score were total length of stay, LOS, duration of antibiotic course, number of surgical procedures, and case mix index. The SOI score functioned well as higher scores were associated with sicker patients. The SOI score is helpful for determining which patients will require longer hospitalizations and more intense treatment in a setting other than the institution of origin.

Comparison of Procalcitonin With Commonly Used Biomarkers and Algorithms for Evaluating Suspected Pediatric Musculoskeletal Infection in the Emergency Department

INTRODUCTION

It is difficult to distinguish between children with infectious versus noninfectious conditions of the musculoskeletal system during initial evaluation. Clinical predictive algorithms potentially support this effort but not without limitations. Procalcitonin (PCT) has been proposed as a biomarker to help differentiate infection from noninfection. This study evaluates the adoption and utility of PCT during initial infection evaluations and assesses test characteristics of commonly used parameters and algorithms.

METHODS

PCT was introduced for initial laboratory evaluation of the suspected musculoskeletal infection. Prospective enrollment occurred from July 2020 to November 2021 with 3 cohorts established after a retrospective review of final diagnoses at the end of treatment: 1) deep infection, 2) superficial infection, and 3) noninfection. Univariate and multivariate logistic regression analysis of parameters and diagnoses was performed. Test characteristics of individual and aggregated parameters were assessed.

RESULTS

Among 258 children evaluated, 188 (72.9%) had PCT drawn during the evaluation. An increase of PCT acquisition from 67.8% to 82.4% occurred over the study timeframe. Eighty-five children were prospectively studied, including those with deep infection (n=21); superficial infection (n=10), and noninfection (n=54). Test characteristics of parameters showed accuracy ranging from 48.2% to 85.9%. PCT >0.1 ng/mL independently predicted deep infection in 84.7% of cases, outperforming white blood cell, C-reactive protein (CRP), and absolute neutrophil count. Using study thresholds for CRP, erythrocyte sedimentation rate, PCT, and Temp improved accuracy to 89.4%.

CONCLUSIONS

PCT is a potentially useful biomarker during the initial assessment of children suspected to have a musculoskeletal infection. Systematic evaluation using a combination of parameters improves the accuracy of assessment and assists predictive judgment under uncertainty. PCT <0.1 ng/mL, erythrocyte sedimentation rate <18 mm/hr, CRP <3.3 mg/dL, and temperature <37.8°C should reasonably reassure clinicians that deep musculoskeletal infection is less likely, given the high negative predictive value and collective accuracy of these parameters.

LEVEL OF EVIDENCE

Level III - Retrospective cohort comparison.